This invention relates to sensors for the sensing and measurement of a variety of parameters including temperature, pressure, etc.
In these arrangements the sensing element, which is subjected to the parameter to be sensed and measured is an optical fibre Fabry-Perot interferometer. Such an interferometer consists of a length of an optical fibre with semi-silvered optically flat ends, which ends thus act as mirrors for the interferometer. The influence of the parameter being sensed, which can be exercised in various ways, e.g. by magneto-strictive means, piezo-electric means, thermal effects, acoustic effects, varies the length of the fibre. Thus detection depends on measuring the changes in the transmitted signals as functions of changes in length of the Fabry-Perot interferometer. Such a Fabry-Perot interferometer may use relatively long optical fibres, e.g. 40 cm or longer, say 100 cm.